Abstract: A new thin film composed of transition metal nitride of Mn₄N has been fabricated successfully by using reactive pulsed laser deposition and DC discharge methods in nitrogen ambient. The electrochemical reaction of the Mn₄N thin film electrode with Li was firstly investigated by the discharge/charge, cyclic voltammetry, and AC impedance spectroscopy measurements. Mn₄N thin film exhibited 420 mAh•g^-1 in the first discharge process, and a nearly 50% irreversible capacity loss occurred in the first cycle. X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure, morphology, and composition of the as-deposited, lithiated, and delithiated Mn₄N thin films. The reversible reaction of the Mn₄N thin film with lithium may involve partial conversion of metal Mn and Li₃N into Mn₄N. It should be responsible for the large capacity loss between the first and the second discharges.

Key words: Pulsed laser deposition, Li ion batteries, Mn₄N, Thin films